[PR] Fix arity of clearInterval, clearTimeout
[PR] Fix arity of clearInterval, clearTimeout

Summary:
It's okay for their argument to be null/undefined, which appears to have been the intended type, but `clearTimeout()` does not make sense.

Fixes type errors in 0.63.x where (valid) code that passed an `?IntervalID` or `?TimeoutID` threw errors.
Pull Request resolved: https://github.com/facebook/flow/pull/5665

Reviewed By: jbrown215

Differential Revision: D8650993

Pulled By: mroch

fbshipit-source-id: d773207fa6e4b8dc67d68e32bfe52838a36eaddf

facebook/flow,AgentME/flow,mroch/flow,AgentME/flow,mroch/flow,facebook/flow,popham/flow,samwgoldman/flow,popham/flow,mroch/flow,samwgoldman/flow,gabelevi/flow,samwgoldman/flow,facebook/flow,samwgoldman/flow,popham/flow,popham/flow,gabelevi/flow,mroch/flow,facebook/flow,AgentME/flow,AgentME/flow,popham/flow,gabelevi/flow,mroch/flow,gabelevi/flow,popham/flow,facebook/flow,samwgoldman/flow,mroch/flow,gabelevi/flow,popham/flow,facebook/flow,samwgoldman/flow,samwgoldman/flow,gabelevi/flow,facebook/flow,mroch/flow,AgentME/flow,gabelevi/flow